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1. Ensure that the ignition switch is at the "LOCK" (OFF) position.
2. Start up the personal computer.
3. Connect special tool MB991827 to special tool MB991824 and the personal
computer.
4. Connect special tool MB991910 to special tool MB991824.
5. Connect special tool MB991910 to the data link connector.
6. Turn the power switch of special tool MB991824 to the "ON" position.
7. Start the MUT-III system on the personal computer.
CAUTION: To prevent damage to scan tool MB991958, always
turn the ignition switch to the "LOCK" (OFF) position
before connecting or disconnecting scan tool
MB991958.
NOTE: When special tool MB991824 is energized, special tool
MB991824 indicator light will be illuminated in a green
color.
NOTE: Disconnecting scan tool MB991958 is the reverse of the
connecting sequence, making sure that the ignition switch
is at the "LOCK" (OFF) position.
2004 Mitsubishi Endeavor LS
2004 HVAC Heater Air Conditioning, Ventilation - Endeavor
Page 2005 of 3870

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.
HOW TO READ AND ERASE DIAGNOSTIC TROUBLE CODES REQUIRED SPECIAL TOOL:
MB991958: Scan Tool (MUT-III Sub Assembly)
MB991824: Vehicle Communication Interface (V.C.I.) MB991827: MUT-III USB Cable MB991910: MUT-III Main Harness A (Vehicles with CAN
communication system)
1. Connect scan tool MB991958 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Select "Interactive Diagnosis" from the start-up screen.
4. Select "System select."
5. Choose "Air Conditioner" from the "BODY" tab.
6. Select "MITSUBISHI."
7. Select "Diagnostic Trouble Code."
8. If a DTC is set, it is shown.
9. Choose "Erase DTCs" to erase the DTC. CAUTION: To prevent damage to scan tool MB991958, always
turn the ignition switch to the "LOCK" (OFF) position
before connecting or disconnecting scan tool
MB991958.
NOTE: If the battery voltage is low, diagnostic trouble codes will
not be set. Check the battery if scan tool MB991958 does
not display.
2004 Mitsubishi Endeavor LS
2004 HVAC Heater Air Conditioning, Ventilation - Endeavor
Page 2007 of 3870
HOW TO READ DATA LIST REQUIRED SPECIAL TOOL:
MB991958: Scan Tool (MUT-III Sub Assembly)
MB991824: Vehicle Communication Interface (V.C.I.) MB991827: MUT-III USB Cable MB991910: MUT-III Main Harness A (Vehicles with CAN
communication system)
1. Connect scan tool MB991958 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Select "Interactive Diagnosis" from the start-up screen.
4. Select "System select."
5. Choose "Air Conditioner" from the "BODY" tab.
6. Select "MITSUBISHI."
7. Select "Data List."
8. Choose an a
ppropriate item and select the "OK" but
ton.
CAUTION: To prevent damage to scan tool MB991958, always
turn the ignition switch to the "LOCK" (OFF) position
before connecting or disconnecting scan tool
MB991958.
2004 Mitsubishi Endeavor LS
2004 HVAC Heater Air Conditioning, Ventilation - Endeavor
Page 2009 of 3870
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.
HOW TO PERFORM ACTUATOR TEST REQUIRED SPECIAL TOOL:
MB991958: Scan Tool (MUT-III Sub Assembly)
MB991824: Vehicle Communication Interface (V.C.I.) MB991827: MUT-III USB Cable MB991910: MUT-III Main Harness A (Vehicles with CAN
communication system)
1. Connect scan tool MB991958 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Select "Interactive Diagnosis" from the start-up screen.
4. Select "System select."
5. Choose "Air Conditioner" from the "BODY" tab.
6. Select "MITSUBISHI."
7. Select "Actuator Test."
8. Choose an a
ppropriate item and select the "OK" but
ton.
CAUTION: To prevent damage to scan tool MB991958, always
turn the ignition switch to the "LOCK" (OFF) position
before connecting or disconnecting scan tool
MB991958.
2004 Mitsubishi Endeavor LS
2004 HVAC Heater Air Conditioning, Ventilation - Endeavor
Page 2011 of 3870

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.
HOW TO DIAGNOSE THE CAN BUS LINES REQUIRED SPECIAL TOOL:
MB991958: Scan Tool (MUT-III Sub Assembly)
MB991824: Vehicle Communication Interface (V.C.I.) MB991827: MUT-III USB Cable MB991910: MUT-III Main Harness A (Vehicles with CAN
communication system)
1. Connect scan tool MB991958 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Select "CAN bus diagnosis" from the start-up screen.
4. When the vehicle information is displayed, confirm that it matches the vehicle
whose CAN bus lines will be diagnosed. If they match, go to Step 8 . If not, go to step 5.
5. Select the "view vehicle information" button.
6. When the vehicle information is displayed, confirm again that it matches the
vehicle which is diagnosed CAN bus line. If they match, go to Step 8 . If not, go to step 5.
7. Select the "OK" button.
8. When the options are displayed, choose the options (mark the check) and then
select "OK". CAUTION: To prevent damage to scan tool MB991958, always
turn the ignition switch to the "LOCK" (OFF) position
before connecting or disconnecting scan tool
MB991958.
2004 Mitsubishi Endeavor LS
2004 HVAC Heater Air Conditioning, Ventilation - Endeavor
Page 2022 of 3870
2. Turn the ignition switch to "ON" position.
3. Diagnose the CAN bus line. Q: Is the check result satisfactory?
YES:
Go to Step 2.
NO:
Repair the CAN bus lines (Refer to
CAN BUS DIAGNOSTICS
TABLE
). Then go to Step 7 .
STEP 2. Recheck for diagnostic trouble code.
Recheck if the DTC is set.
1. Erase the DTC.
2. Turn the ignition switch to "ON" position.
3. Check if the DTC is set.
Q: Is the check result satisfactory?
YES:
It can be assumed that this malfunction is intermittent.
Refer to
HOW TO USE TROUBLESHOOTING/ INSPECTION
SERVICE POINTS
.
NO:
Go to Step 3.
STEP 3. Using scan tool MB991958, check data list item 02: Ambient air
temperature sensor.
1. Connect scan tool MB991958 to the data link connec
tor.
CAUTION: To prevent damage to scan tool MB991958,
always turn the ignition switch to the
"LOCK" (OFF) position before connecting or
disconnecting scan tool MB991958.
2004 Mitsubishi Endeavor LS
2004 HVAC Heater Air Conditioning, Ventilation - Endeavor
Page 2024 of 3870
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.
2. Start the engine.
3. Check the data list.
Item 02: Ambient air temperature sensor.
Check that the ambient temperature matches the displayed value on
the scan tool.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor within the specified range?
YES:
Replace the A/C-ECU. Then go to Step 7 .
NO:
Go to Step 4.
STEP 4. Check A/C-ECU connectors C-16, C-17 and ambient air
temperature sensor connector A-22 for loose, corroded or damaged
terminals, or terminals pushed back in the connector.NOTE: When this DTC is set and the system is fail-safe
status, the value of service data displays 20°C.
2004 Mitsubishi Endeavor LS
2004 HVAC Heater Air Conditioning, Ventilation - Endeavor
Page 2034 of 3870
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.
2. Turn the ignition switch to the "ON" position.
3. Check if the DTC is set.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the check result satisfactory?
YES:
The procedure is complete.
NO:
Return to Step 1 .
DTC B1021, B1022: AIR THERMO SENSOR SYSTEM
2004 Mitsubishi Endeavor LS
2004 HVAC Heater Air Conditioning, Ventilation - Endeavor